Detroit DD8 vs Cummins L9

[chunker21]

Possibly addressed before but what advantages or disadvantages to either engine. Problems, quirks, etc. Does the DD have the DEF head issues? Availability of servicing? Drivability and fuel mileage? On the Force the Dynamax site says Cummins, dealer stop only. In today's market is there "dealer stock"? Question is also why? Why have 2 similar performance engines in the same coach?

 

[rcraighughes1]

All moving forward will be Detroit (all under same umbrella now) half 21s Cummins second half 21s Detroit 22 plus all Detroit
Dealer stock and a few 21s still got the Cummins
XLs still get the Cummins

 

[chunker21]

All moving forward will be Detroit (all under same umbrella now) half 21s Cummins second half 21s Detroit 22 plus all Detroit
Dealer stock and a few 21s still got the Cummins
XLs still get the Cummins

Thanks I did another search of the topic and got much of what you said. Since lately everything is fluid and subject to change I didn't know how what was the current party line. From what I read there seems to be a bit of advantage to DD for RV use especially since few if any RVs will ever achieve the mileage where rebuild is necessary. I wonder if there are any real "dealer stock" RVs around?

 

[1HasBeen]

https://www.truckinginfo.com/101372...over-medium-duty-engine-production-to-cummins


"The new partnership will mean Daimler’s Detriot DD5 and DD8 medium-duty engines, introduced in 2016 and 2018, respectively, will also be phased out."

 

[CyberShanks!]

All moving forward will be Detroit (all under same umbrella now) half 21s Cummins second half 21s Detroit 22 plus all Detroit
Dealer stock and a few 21s still got the Cummins
XLs still get the Cummins

^ is why we went XL. Cummins fan here, and now that I've driven our new XL, it has some amazing power.


Jim

 

[Invisibleman]

I have a 21 Force with the Detroit DD8. I did a lot of research on this in advance, but as a new engine for this application I had little but data sheets to go by. Ultimately it didn't matter as the Force and DX3 both were being shipped with Detroit DD8. I my opinion, its likely not much difference in the Detroit vs Cummins. They are similar, albeit the DD8 being around a 7% reduction in torque. Now with 10,000 miles of seat time under my belt, I would likely have done it differently, $$ considerations aside. For me the DD8 is not enough engine. That's just my opinion. Here's a link on another post here about the DD8 performance/fuel economy. As can be seen therein, each to his own. The opinions will vary, often widely.

https://www.forestriverforums.com/f...-with-detroit-dd8-fuel-efficiency-242801.html

If you can afford it, get the XL, if for nothing else the larger engine. You wont regret it.

 

[CyberShanks!]

Very sorry to hear that, and I know that the 34kd is a few foot shorter than your 37ts, but I can confirm the XL does have a nice level of power. Really looking forward to spring when I have 12-13k lbs behind it (still trying to put our storage shed back together).


Jim